Handling & Storage
What Is Lyophilization? Freeze-Drying Peptides Explained
Freezing, primary drying, secondary drying — and why the appearance of the cake in your vial tells you something about the process that produced it.
August 18, 2026 · 6 min read · Novanta Research
The three stages
Lyophilization removes water from a frozen solution by sublimation — ice converting directly to vapour under vacuum — rather than by evaporation. The peptide never passes through a concentrated liquid phase, which is what protects it.
The process runs in three stages: freezing the solution solid, primary drying to sublime the ice under vacuum, and secondary drying at slightly higher temperature to remove water still bound to the peptide.
- Freezing — the solution is solidified, often with a controlled ramp
- Primary drying — ice sublimes under vacuum
- Secondary drying — bound water is driven off
Reading the cake
A well-lyophilized vial contains a uniform, structured cake that occupies roughly the volume of the original solution. It dissolves quickly and completely when diluent is added.
A collapsed, shrunken or glassy layer at the bottom suggests the product warmed above its critical temperature during drying. That does not automatically mean degraded material, but it does mean the process ran outside its intended window and residual moisture is likely higher.
Why it matters downstream
Residual moisture is the single biggest predictor of how long a lyophilized peptide stays intact in storage. Water left behind after drying will keep driving hydrolysis and deamidation slowly for the life of the vial, which is why moisture content appears on thorough certificates.
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For laboratory and research use only. Not for human or veterinary consumption. Novanta Research is not a compounding pharmacy and nothing in this article is medical advice or a claim that any compound diagnoses, treats, cures or prevents any condition.